Go Coogs' wrote:The difference is great, but I still want to change the mechanical fan for electric fans which will give me another 5-10 more HP
People still fall for that sales pitch?
I'm sure your mechanical fan has a clutch on it. So once you hit the gas pedal, the fan is freewheeling, and taking next-to-no horsepower to run. And those stupid claims of "X# of HP increase" never take into account
the extra load on the alternator to run the electric fan... there is
that... which factored in, gives you a net horsepower gain of... right around zero.
Paul wrote:Rumps, don't forget to get a underdrive pulley set for it....you'll see an EASY 2-3mpg better and at least 10hp.
Another sales pitch that tells only half the story... all well and good, as long as you're on the freeway all day. Around town, stoplight-to-stoplight (where you want the power increase)...
not so much.
I wish I had a dollar for every time I had to explain how silly the concept is back in my auto electrician days.
Yes, it takes less power to turn the alternator at a slower speed -- this much is true.
Changing the speed at which the alternator turns doesn't change a vehicle's electrical consumption one iota -- unless the company marketing the underdrive pullies has completely rewritten some basic scientific shit, and have figured out a way to get something for nothing, electrically, in which case they should probably be working on some green-energy project.
Newsflash -- it takes the exact same amount of energy (in this case, from the alternator via engine power) to run the vehicles electrical system, regardless of pully size. When you slow down the alternator, it won't keep up with the electrical demand at idle (no, seriously -- those guys designing the car actually put some thought into it). Instead, it dips into battery reserve... and as soon as you rev the engine...
are we following? Good.
As soon as you rev the engine, it loads the alternator to replace the charge in the battery.
To anyone with a brain and a basic understanding of this shit, this results in
a horsepower/torque gain at idle, and a LOSS OFF THE LINE.
Period. All those laws of physics and thermodynamics and all that stuff all agree, 100%... because it's the
only way that can work.
But it's a great marketing scam, though, and is useful on a track car. A daily, around-town driver?
That's just silly.